1. Field of the Invention
This invention relates to a new and distinct variety or cultivar of the deciduous tree, Betula nigra, commonly known as river birch.
2. Description of the Related Art
River birch trees are native to stream banks and wet areas over much of the eastern half of the United States extending westward to central and northern Oklahoma. A river birch tree is typically about 30 to 60 feet tall having a broad spreading crown and a short, thick, soon-branching trunk that is rarely larger than between about 12 and 24 inches in diameter. The bark is reddish brown or silvery gray, shiny and becomes fissured, separating into papery scales.
The inventor of this new and distinct river birch gathered a large quantity of seed from the western most native river birch seedlings in central Oklahoma in 1986. but none of these gathered seeds germinated. In 1987, about three pounds of additional seeds were gathered from the western most native birch tree seedlings having the lightest bark in central Oklahoma. These trees were located along a narrow steam that was typically without flowing water for six months or more each year. After planting, only a fraction of the seeds germinated and most of the seedlings were weak and did not survive the first summer. There were, however, three vigorous seedlings that survived and were planted into a field. Two of these seedlings were typical loose, open-branched trees and considered of little value.
The third seedling was more ornamental with denser branching, darker leaves and slightly slower growth. In 1992, when the seedling was six years old, viable seeds were produced. The resulting seedlings from these produced seeds were planted in a field where they grew for five years before producing viable seed. Seed was collected from one of these seedlings having lighter bark than the others. Seedlings from this last collection of seeds were planted and allowed to grow.
The new plant of this invention was one of the seedlings grown from the last collection of seeds and is distinctly different from its ancestors, the parent plant or its other siblings. The new plant is characterized as having creamy-white bark during late summer, fall and winter. The white bark develops at a young age, when most stems are about 0.75 to 1.0 inch in diameter. The leaves are dark green of moderate size and turn yellow-gold in the fall. The color of the bark of a typical river birch tree is a cinnamon tan to light brown. While the bark of some river birch trees develop a creamy tan color on larger stems, the present cultivar differs from other river birch trees known to the inventor as having bark that is creamy-white once the stems start to peel, even at a very young age when the stems have diameters of between about 0.75 and 1 inch.
The river birch that is known to the inventor and appears to be the most similar to that of the claimed river birch tree is the Dura-Heat® river birch tree. However, the Dura-Heat® river birch may be differentiated from the current invention as having bark coloration under the peeling bark that is darker as well as rougher in texture. The rougher texture of the exposed bark under the peeling bark of the Dura-Heat® river birch tree is due to slender pieces of bark that are loose and thereby roughen the bark surface.
This new and distinct plant was first asexually reproduced by rooting softwood cuttings from the original plant near Stillwater, Okla. The asexually reproduced plants show the unique features that characterize this new river birch tree indicating that the unique features of this plant are stable through its successive generations of asexual reproduction.